High maneuverability towcraft

ABSTRACT

An open-backed towable watercraft (towcraft) which is maneuverable from side-to-side by the intuitive leaning action of one or more riders thereon. The towcraft consists of a partial hull structure, upwardly curved at the bow end with a predominantly flat bottom and stern; and, an inflated, or other cushioned, upper portion which is fitted with handles for the riders to securely grasp. At least three downward-projecting fins are removably attached to the partial hull structure. A first fin of sufficient size and draft is ventrally located along the craft&#39;s centerline, at its front. A second and third fin, smaller in size and draft to the ventral fin, are laterally spaced-apart, preferably, at a station aft of the craft&#39;s center of gravity. The towline attachment to the front of the towcraft is at a point above the craft&#39;s operative waterline and situated such that the towline line-of-force intersects, or very nearly intersects, the ventral fin&#39;s effective zero-moment vertical center line for all normal towline attitudes.

The present invention relates to recreational watercraft of the typewhich is directly pulled or towed behind power boats, personalwatercraft (PWC), and the like. This invention claims priority by way ofreference to Provisional Application For Patent Ser. No. 60/529,813filed on Dec. 16, 2003, and Provisional Application For Patent Ser. No.60/544,432 filed on Feb. 16, 2004.

BACKGROUND OF THE INVENTION

A primary object of the present invention is to devise the most basichighly maneuverable towcraft that one rider, or multiple riders canoperate, not only from the standpoint of construction and cost, but alsoin its operation.

SUMMARY OF THE INVENTION

This invention consists of a thin, lightweight, structural lower hullcomprising the lower-most part of the towcraft, and a cushioned upperpart. The cushioned upper, consisting of either foam and one or moreinflation chambers, or a combination of both, presents a resilientsurface to the rider and also functions as a flotation means.

The general shape of the towcraft resembles that of an elongatedhorseshoe. In one embodiment, the side and front portion above the hullconsists of one or more fabric-covered inflation chambers, while theupper surface of the flat floor is foam covered, or, more preferably,has an inflated half-tube on which a kneeling person may straddle.Handles are provided in the cover as a simple means whereby one rider,or multiple riders, may shift their weight from side-to-side withoutchanging their grip. The stern end of the towcraft is left open therebymaking it easy for riders to climb aboard. Also, the flat exposed floorat the stern end allows any collected water to drain away. Further, theflat termination of the floor at the stern end counters any CoandaEffect.

The bow end of the hull is made to sweep upwards and back a shortdistance above the craft's waterline. Near its upper extent, lying alongthe centerline of the towcraft, a D-ring, strap, or other robust towlineattachment means is provided. Immediately below the simple, fixed,towline attachment point is the areal moment center of a fixed primarywater-engaging device consisting of a ventral fin. The ventral fin isremovably attached to the bow-end of the hull by its neck portion. As aresult of the ventral fin's forward mounting, and its characteristicbalanced, or nearly balanced (front/rear area) design, the forward-mostend of the ventral fin can extend beyond the front of the towcraft'shull. Therefore, it is preferable that the leading edge of the ventralfin is itself cushioned with a layer of rubber or other elastomericmaterial.

A short distance astern of the ventral fin, two spaced-apart, slightlytoed-out, trailing fins are provided. When a leaning action by therider(s) ensues, the drag differential between its left and right sidecauses the towcraft to rotate in the direction of the lean, therebycausing the it to proceed in that direction.

It should be noted that the substitution or addition of flexibletrailing fins, or pivotable trailing fins, or curved trailing fins, anextra set of spaced-apart trailing fins positioned aft of the first set,an operable pivoting handlebar, or a stationary one with twist gripswhich manipulate alternate pivoting fins sequentially, or othercontemplated embodiments do not depart from the scope of the invention.

DESCRIPTION OF THE DRAWINGS

With reference to FIG. 1, the present invention consists of a hull 1, abow-end 1A, a stern-end 1B, inflated upper 2 (shown covered), ventralfin 3, ventral fin areal moment center 3A, spaced-apart trailing fins 4Aand 4B, towline 5, towline attachment point 6, and inflated half-tube 7.

I. A high maneuverability towcraft comprising: a means for ensuring thatthe towline line-of-force (always) intersects, or nearly intersects, theprimary water-engaging device's areal moment's vertical centerlineduring all normal on-the-water operations; an above-the-waterlinetowline attachment means; a means whereby more than one rider maycooperatively participate in maneuvering the towcraft; a means for easyingress onto the towcraft from the rear of the towcraft; a means wherebythe rider(s) may secure a sure grip on the towcraft while at the sametime allow for aggressive weight-shifting. II. The high maneuverabilitytowcraft of claim 1, wherein the towline is simply attached to a pointdirectly above the forward-mounted ventral fin's (areal) effectivezero-moment('s) vertical center line, and two parallel-aligned, orslightly toed-out, spaced-apart trailing fins (slightly toed-out) suchthat hull rotation is induced upon a rider(s) leaning or weight-shiftingaction, and an elastomer-covered, flat, rigid, floor termination at theextreme stern-end of the towcraft whereby collected water isautomatically drained away, and a centered, longitudinal, inflatedhalf-tube whereby (the) kneeling rider(s) are further supported bothlaterally and vertically.